1. Field of the invention
This invention relates to drive mechanisms for rotating crankshafts for use in machine tools for working on crankshafts.
2. Description of the prior art
Machine tools for machining crankshafts by convention have head and tail stocks carrying chucks in which the ends of the crankshafts or other work pieces are supported for the machining operations.
UK Patent Specification No. 1435674 shows a difficult conventional arrangement. UK Patent Specification No. 1566689 discloses a machine tool for crankshaft machining in which a crankshaft is supported between head stocks for simultaneously milling two crank ends of the crankshaft. UK Patent Specification No. 1559550 discloses a crankshaft journal manufacturing machine tool having a bed with two space bearings supporting axially aligned chucks in which the ends of a crankshaft are engaged. Two milling units have a cross-slide carrying a tool drum provided with a rotary annual milling tool at its end face. The tool has inward directly cutting edges. An additional work piece support is associated with each milling unit to move with the unit to support the crankshaft at the location where the milling operation is carried out.
UK Patent Application No. 2130135 discloses a back rest for use in a milling machine for milling long work pieces such as crankshafts and comprises a supporting jaw which is adapted to be disposed under the work piece under the centre of the length of the work piece. The support can also provide for work piece rotation.
An object of the present invention is to provide a driving arrangement for rotating a crankshaft about a required axis so that machining or other operations can be performed on the ends of the crankshaft.